Sure. I would have hoped anyone sane understood this. Or probably they use some supermarket $20 amplifiers.
Err.rh! That means you are setting your Volume Control to suit the gear rather than the music.
That's OK for "crappy, compressed program material" but 'real life' music has an exact loudness that good recording engineers can set within 1dB.
If you play a piano recording too softly, it doesn't sound further away. It sounds too small. But if you don't make your own recordings of music (as opposed to "crappy, compressed program material"), you are probably not bothered.
Real music has dynamic range. Remember 'dynamic range'? Soft bits and loud bits. This millenium, when for the first time in history, readily available recording gear can exceed the dynamic range of 'real life' music, we are obsessed with making "crappy, compressed program material".
Exceptions like RLJ are rare today. In da old days, the BBC would receive letters saying, "I could hear the engineer move the fader up during the Adagietto of Mahler's 5th in last night's live broadcast from the Albert Hall."
_____________
To find out if your musical tastes require a bigger amp or more sensitive speakers to avoid clipping, try http://www.diyaudio.com/forums/multi-way/204857-test-how-much-voltage-power-do-your-speakers-need.html
It's all down to the setting of your Volume Control and the 'music' you play.
______________
Mr. Marsh, I've got a problem. I dunno how to design a 1000+W/channel 8R amp. and I'd be afraid to do so.
I might just have to accept it clipping
Actually no. If I adjust to have 0 dB Fs from my DAC just below the
clipping point of my amp the playback level in my room is way to loud.
But ok, listen habits and efficiency of speakers vary all over the place.
A 84 dB/W/m speaker like in Bobs example would not be a good choice
if you want to play "loud", though.
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Seems to be the general consensus on here. I agree on the whole but with the exception of modern electronic dance music. This is one style of music where excessive compression works.
Hi Bob,
It cant be dismissed if you dont know there is a problem and dont deal with it so you dont have that problem anymore. But we here ought to know better.... I would think. To do a CFA amp at 50W was nuts to me. You might only need a 5W to be loud... but not clean and not producing harmonics from clipping. And, of course we test for thd withOut clipping. yet people say amps sound different. Hmmm. I wanted 250W at least and I have 92dB effecient woofers. I said recently, somewhere around here, that amps used to have clipping indicators on them. They were left off because of dealers--- they didnt like them showing clipping when they played them in demo's.
Its a good subject and maybe we can design an add-on clipping indicator so all can see what thier amps are doing most/some of the time. Eventually, by listening tests, it was decided by the Gods in power at the time to put in clipping delays/averagers and thus indicate more accurately what was being percieved. But still the dealers won out. Couldnt play thier low power amps without clipping and below clipping wasnt loud enough. And, higher power would cost too much and sales would fall. So here we have a hidden distortion generator which the public isnt told about -- just the thd/Im spec.
How good are DBL when amps are clipping and thresholds of audibility in clipping are exceeded... what can be drawn from such test results and comments about the sound of an amp or speaker for what is preferred et al? Is it inconceivable that people would want to limit the HF response when amps are clipping and producing HF harmonics that are annoying? It puts doubt in the findings.
Following that issue came dividing up the power spectrum with electronic cross-overs -- as the bass is a likely cause of much of the clipping, it's distortion from clipping could be contained to a more narrow range of freqs and the other amps for mid/high could be lower power and still not clip.
--- take it from there --- expand --
Thx-RNMarsh
Hi Richard,
Yes, active crossovers and bi-amping or tri-amping helps a lot in many ways.
Interestingly, the major cause of the clipping on the Rickey Lee Jones cut was a very serious thwack of a snare drum. Another interesting thing about that album is that it is recorded on the CD at a noticeably lower level than most other CDs in order to leave room for the uncompressed peaks. After listing to other CDs, when I put this one on, I have to turn up the volume to achieve the same perceived average playing level.
As an aside, I should mention that limiting and compression is always a matter of degree, and I honestly don't know for sure that there is not some degree of limiting/compression even in the Ricky Lee Jones album.
Cheers,
Bob
These are good points, and we must never forget that having the output stage crash into rails with lots of nasty ripple is much worse than just a sharp clean clip.
Many modern professional amplifiers now use switching power supplies with power factor correction, and this helps matters like this to some extent. The PFC enables the amplifier to make better use of the mains voltage, given its impedance, sag and waveform. Of course, SMPS have their own set of issues and are fairly complex to design. It is wise not to skimp on the reservoir capacitors in a power amp with SMPS just because the ripple frequency is high, BTW.
Cheers,
Bob
Not sure what you are talking about here. Is it a dynamic sort of level control like a compressor or agc that works on signal levels above a certain voltage, or is it essentially a soft clip?
Cheers,
Bob
One can always adjust the volume in one's system so that 0dBFS will not clip any part of the playback chain. That is clear, but that is not the point. If one does that on program material with very high crest factor, one will not experience realistic average listening levels.
You would be surprised how many exceptionally good high-end loudspeakers have efficiency only in the neighborhood of 84dB.
Cheers,
Bob
yes Richard is playing games to exaggerate magnetic effects - open/untwisted wire with large loop area in contact with steel
but we all see, some even make measurements with better soundcards, say the ESI Juli@ with -130 dB spot noise floors where IMD from the signal "going through" the Ni plated steel RCA, the PC case, ect should be visible everywhere by his “avoid steel cases, leads” rubric
and the purported ferromagnetic distortion "problem" just isn't - you have to construct the special situations to get Richard's measurements
just twist or coax, airspace with standoff, don't allow large high current loop area in layout or wiring, don't use solenoid coils without thinking about, allowing for the mag field's reach into space
but we all see, some even make measurements with better soundcards, say the ESI Juli@ with -130 dB spot noise floors where IMD from the signal "going through" the Ni plated steel RCA, the PC case, ect should be visible everywhere by his “avoid steel cases, leads” rubric
and the purported ferromagnetic distortion "problem" just isn't - you have to construct the special situations to get Richard's measurements
just twist or coax, airspace with standoff, don't allow large high current loop area in layout or wiring, don't use solenoid coils without thinking about, allowing for the mag field's reach into space
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Err.rh! That means you are setting your Volume Control to suit the gear rather than the music.
That's OK for "crappy, compressed program material" but 'real life' music has an exact loudness that good recording engineers can set within 1dB.
If you play a piano recording too softly, it doesn't sound further away. It sounds too small. But if you don't make your own recordings of music (as opposed to "crappy, compressed program material"), you are probably not bothered.
Real music has dynamic range. Remember 'dynamic range'? Soft bits and loud bits. This millenium, when for the first time in history, readily available recording gear can exceed the dynamic range of 'real life' music, we are obsessed with making "crappy, compressed program material".
Exceptions like RLJ are rare today. In da old days, the BBC would receive letters saying, "I could hear the engineer move the fader up during the Adagietto of Mahler's 5th in last night's live broadcast from the Albert Hall."
_____________
To find out if your musical tastes require a bigger amp or more sensitive speakers to avoid clipping, try http://www.diyaudio.com/forums/multi-way/204857-test-how-much-voltage-power-do-your-speakers-need.html
It's all down to the setting of your Volume Control and the 'music' you play.
______________
Mr. Marsh, I've got a problem. I dunno how to design a 1000+W/channel 8R amp. and I'd be afraid to do so.
Sounds like I inadvertantly came up with a new term, "crappy compressed program material" abbreviated CCPM.
.Cheers,
Bob
Hi Guys
Krglee, most kilowatt amps are actually bridged amps - so "jus"t 500W each rated for 4R bridged as 1,000W at 8R. Just 64Vpk per amp at 16A. usually 8-16 output devices per amplifier (total is twice this then). Easy, no?
A thousand watts per channel of CCPM would be well beyond the human scale of tolerance for both the sheer loudness and the exponential increase of the C of the CPM.
Have fun
Kevin O'Connor
Krglee, most kilowatt amps are actually bridged amps - so "jus"t 500W each rated for 4R bridged as 1,000W at 8R. Just 64Vpk per amp at 16A. usually 8-16 output devices per amplifier (total is twice this then). Easy, no?
A thousand watts per channel of CCPM would be well beyond the human scale of tolerance for both the sheer loudness and the exponential increase of the C of the CPM.
Have fun
Kevin O'Connor
Lot has been said about clipping, without any real world examples. May we see some examples of bad clipping behavior? Or, badly behaving amplifiers, namely? I assume we are trying to speak about serious designs and high quality designs here. And also not about 50W/8ohm amplifiers, regardless how low THD they would have.
absolutes aren't so useful - windup is a reality as are storage times in saturation
so the question should be what is audibly objectional worsening of clipping? 1 us, or 100 us of recovery - any real listening evidence?
temporal masking is strong for sub ms scale - but require "conventionally audible" components - which wouldn't include few tens of microseconds rail sticking
so the question should be what is audibly objectional worsening of clipping? 1 us, or 100 us of recovery - any real listening evidence?
temporal masking is strong for sub ms scale - but require "conventionally audible" components - which wouldn't include few tens of microseconds rail sticking
There are plenty of old school domestic amplifiers that exhibit sticking, with associated very fast slew rate recovery.
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